Sports nutrition is a concept that dates back thousands of years. Athletes figured out early on that what they put into their bodies will directly impact their performance. Let's go over some of the basics of food and terms you may notice when people talk about food.
While a diet can be a way people go on to change their weight, the definition also applies to anything a person eats or drinks regularly, the kind of food a person eats and eating habits. Athletes, and non-athletes need proper nutrients from various sources, including carbohydrates, fats, protein, vitamins, minerals and water, in order for their bodies to function properly.
A diet is considered nutritious if it meets all of a person's macro and micronutrient demands; of course, these needs vary depending on your own personal fitness goals and your lifestyle. Think about it like this, a professional basketball player isn't going to have the same needs in terms of their daily diet. The pro-athlete will likely need a lot of energy in order to properly carry out tasks.
It's helpful to look at food as fuel for you body. The calories you eat simply give you energy, and since everyone has different needs. When thinking about your diet, focus on the foods that make you feel the best, and what you enjoy consuming. And most importantly, don't pay too much attention on anyone else's meals - you're eating for yourself, not others.